Re: [alsa-devel] [PATCH 2/2] ASoC: tegra: use sound pcm library for substream dma buffer

At Mon, 2 Jul 2012 14:24:33 +0530, Laxman Dewangan wrote:

The sound pcm library support the writecombine DMA buffer allocation/deallocation/mapping and hence using the APIs form sound pcm library inplace of implementing the same locally.

Signed-off-by: Laxman Dewangan ldewangan@nvidia.com

Changes from V1: Changes done to use the existing APIs for sound pcm memory management which is now supporting writecombine.

sound/soc/tegra/tegra_pcm.c | 112 ++++++++++-------------------------------- 1 files changed, 27 insertions(+), 85 deletions(-)

diff --git a/sound/soc/tegra/tegra_pcm.c b/sound/soc/tegra/tegra_pcm.c index 127348d..ec1fa25 100644 --- a/sound/soc/tegra/tegra_pcm.c +++ b/sound/soc/tegra/tegra_pcm.c @@ -202,8 +202,14 @@ static int tegra_pcm_hw_params(struct snd_pcm_substream *substream, { struct snd_pcm_runtime *runtime = substream->runtime; struct tegra_runtime_data *prtd = runtime->private_data;

• int ret;

• snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);

• ret = snd_pcm_lib_malloc_pages(substream,

• 		params_buffer_bytes(params));
  

• if (ret < 0) {

• pr_err("page allocation failed, err %d\n", ret);
  

Do you really want to spew error messages at each time?

• return ret;
  

• }

  prtd->dma_req[0].size = params_period_bytes(params); prtd->dma_req[1].size = prtd->dma_req[0].size;

@@ -213,9 +219,7 @@ static int tegra_pcm_hw_params(struct snd_pcm_substream *substream,

static int tegra_pcm_hw_free(struct snd_pcm_substream *substream) {

• snd_pcm_set_runtime_buffer(substream, NULL);
• return 0;

• return snd_pcm_lib_free_pages(substream);

}

static int tegra_pcm_trigger(struct snd_pcm_substream *substream, int cmd) @@ -263,18 +267,6 @@ static snd_pcm_uframes_t tegra_pcm_pointer(struct snd_pcm_substream *substream) return prtd->period_index * runtime->period_size; }

-static int tegra_pcm_mmap(struct snd_pcm_substream *substream,

• 		struct vm_area_struct *vma)
  

-{

• struct snd_pcm_runtime *runtime = substream->runtime;
• return dma_mmap_writecombine(substream->pcm->card->dev, vma,

• 			runtime->dma_area,
  

• 			runtime->dma_addr,
  

• 			runtime->dma_bytes);
  

-}

static struct snd_pcm_ops tegra_pcm_ops = { .open = tegra_pcm_open, .close = tegra_pcm_close, @@ -283,87 +275,37 @@ static struct snd_pcm_ops tegra_pcm_ops = { .hw_free = tegra_pcm_hw_free, .trigger = tegra_pcm_trigger, .pointer = tegra_pcm_pointer,

• .mmap = tegra_pcm_mmap,

• .mmap = snd_pcm_lib_default_mmap,

You can simply remove .mmap definition. NULL falls back to the default mmap handler.

};

-static int tegra_pcm_preallocate_dma_buffer(struct snd_pcm *pcm, int stream) -{

• struct snd_pcm_substream *substream = pcm->streams[stream].substream;
• struct snd_dma_buffer *buf = &substream->dma_buffer;
• size_t size = tegra_pcm_hardware.buffer_bytes_max;
• buf->area = dma_alloc_writecombine(pcm->card->dev, size,

• 				&buf->addr, GFP_KERNEL);
  

• if (!buf->area)

• return -ENOMEM;
  

• buf->dev.type = SNDRV_DMA_TYPE_DEV;
• buf->dev.dev = pcm->card->dev;
• buf->private_data = NULL;
• buf->bytes = size;
• return 0;

-}

-static void tegra_pcm_deallocate_dma_buffer(struct snd_pcm *pcm, int stream) -{

• struct snd_pcm_substream *substream;
• struct snd_dma_buffer *buf;
• substream = pcm->streams[stream].substream;
• if (!substream)

• return;
  

• buf = &substream->dma_buffer;
• if (!buf->area)

• return;
  

• dma_free_writecombine(pcm->card->dev, buf->bytes,

• 		buf->area, buf->addr);
  

• buf->area = NULL;

-}

-static u64 tegra_dma_mask = DMA_BIT_MASK(32);

+#define TEGRA_PCM_PREALLOC_BUFFER (32 * 1024) +#define TEGRA_PCM_PREALLOC_BUFFER_MAX (32 * 1024) static int tegra_pcm_new(struct snd_soc_pcm_runtime *rtd) {

• struct snd_card *card = rtd->card->snd_card; struct snd_pcm *pcm = rtd->pcm;
• int ret = 0;
• if (!card->dev->dma_mask)

• card->dev->dma_mask = &tegra_dma_mask;
  

• if (!card->dev->coherent_dma_mask)

• card->dev->coherent_dma_mask = DMA_BIT_MASK(32);
  

The mask setup is still required even if you use the preallocation helper.

• if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream) {

• ret = tegra_pcm_preallocate_dma_buffer(pcm,
  

• 				SNDRV_PCM_STREAM_PLAYBACK);
  

• if (ret)
  

• 	goto err;
  

• }
• if (pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream) {

• ret = tegra_pcm_preallocate_dma_buffer(pcm,
  

• 				SNDRV_PCM_STREAM_CAPTURE);
  

• if (ret)
  

• 	goto err_free_play;
  

• struct snd_card *card = rtd->card->snd_card;
• int retval = 0;
• if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream ||

• 	pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream) {
  

You can omit this check. snd_pcm_lib_preallocate_pages_for_all() will ignore the streams that have no substreams assigned.

Takashi

• retval =  snd_pcm_lib_preallocate_pages_for_all(pcm,
  

• 		SNDRV_DMA_TYPE_DEV_WC,
  

• 		card->dev,
  

• 		TEGRA_PCM_PREALLOC_BUFFER,
  

• 		TEGRA_PCM_PREALLOC_BUFFER_MAX);
  

• if (retval < 0)
  

• 	dev_err(card->dev,
  

• 		"dma buffer pre-alloc failied %d\n", retval);
  

  }

• return 0;

-err_free_play:

• tegra_pcm_deallocate_dma_buffer(pcm, SNDRV_PCM_STREAM_PLAYBACK);

-err:

• return ret;

• return retval;

}

static void tegra_pcm_free(struct snd_pcm *pcm) {

• tegra_pcm_deallocate_dma_buffer(pcm, SNDRV_PCM_STREAM_CAPTURE);
• tegra_pcm_deallocate_dma_buffer(pcm, SNDRV_PCM_STREAM_PLAYBACK);

• snd_pcm_lib_preallocate_free_for_all(pcm);

}

static struct snd_soc_platform_driver tegra_pcm_platform = { .ops = &tegra_pcm_ops, .pcm_new = tegra_pcm_new, -- 1.7.1.1